GILD DMG Mori AG

Gilead Sciences Inc. (GILD) said on Thursday it filed a lawsuit against Israeli-based Teva Pharmaceutical Industries Inc. (TEVA) and its U.S. subsidiary for infringement of two patents tied to two of its HIV drugs.

The action from Gilead comes a little over a month after the company warned it had 45 days to file a lawsuit against Teva, after Teva's submission to manufacture and market a generic version of the HIV drug Atripla.

The lawsuit isn't the first time the two drug companies have sparred over HIV and AIDS drugs. Gilead, a leading maker of AIDS treatments, sued Teva in December to prevent it from making a generic version of HIV drug Truvada until 2021.

Gilead's latest lawsuit is associated with patents over a component found in both Truvada and Atripla.

Gilead said Atripla is currently protected by 15 patents, which are listed in the Food and Drug Administration's products list, and claims all 15 would need to be invalidated or expired before a generic version of the drug could appear on the market.

Teva has alleged that the two patents licensed to Gilead are invalid, unenforceable and wouldn't be infringed by Teva's manufacture, use or sale of the product described in its latest submission. A spokesman from the company wasn't immediately available to comment on the latest lawsuit filing.

Last year, Teva challenged the validity of the same two patents in its ongoing drug application for Truvada. The lawsuit in that case is still ongoing.

In 2008, Gilead reported Truvada sales increased 33% to $2.11 billion. Atripla sales, meanwhile, surged 74% to $1.57 billion during the year.

Shares for Gilead were inactive in after-hours trading at $44.20, while shares for Teva were down 0.5% to $44.74.

- By John Kell, Dow Jones Newswires; 201-938-5285; john.kell@dowjones.com